THE ROSE SAW-FLY. 525 



and connection, which in particular cases if we fail to dis- 

 cover, it is rather to be attributed to our own ignorance and 

 short-sightedness than to a]iy want of harmony and regu- 

 larity in the plan of the Creator. In considering the resem- 

 blances of species, we cannot fail to admire the care that 

 has been taken, by almost insensible shades of difference 

 among them, or by peculiar circumstances controlling their 

 distribution, their habits of life, and their choice of food, 

 to prevent them from commingling, whereby each species 

 is made to preserve forever its individual identity. 



The saw-fly of the rose, which, as it does not seeiji to 

 have been described before, may be 

 called Selandria Rosce (Fig. 245), from ^''^- '^■ 



its favorite plant, so nearly resembles 

 the slug-worm saw-fly as not to be 

 distinguished therefrom except by a 

 practised observer. It is also very 

 much like Selandria harda, Vitis, and pygmcea, but has not 

 the red thorax of these three closely allied species. It is 

 of a deep and shining black color. The first two pairs 

 of legs are brownish-gray or dirty white, except the thighs, 

 which are almost entirely black. The hind legs are black, 

 with whitish knees. The wings are smoky, and transparent, 

 with dark brown veins, and a brown spot near the middle 

 of the edge of the first pair. The body of the male is a 

 little more than three twentieths of an inch long, that of 

 the female one fifth of an inch or more, and the wings 

 expand nearly or quite two fifths of an inch. These saw- 

 flies come out of the ground, at various times, between 

 the 20th of May and the middle of June, during which 

 period they pair and lay their eggs. The females do not 

 fly much, and may be seen, during most of the day, resting 

 on the leaves, and, when touched, they draw up their legs, 

 and fall to the ground. The males are more active, fly 

 from one rose-bush to another, and hover around their 

 sluggish partners. The latter, when about to lay their 



